yes water wetter is great ..drops it about 6 degrees...check your system for air pocket and burp it out ..also check your fan and make shure its coming on at the rite time

 

I would also say leave the 180 stat and check your cap pressure make sure its the right psi, i think 16 and up is good. Its a good idea to use distilled water, because tap water has to many minerals in it forming deposits and eventually clogs everything up. And if you use well water its even worse, trust me i know from experience on this one. Also is you rebuild fresh? New motors run hotter untill they loosen up a bit. Also just cause it hits 205, doesnt mean it will go above that on a hot day, it might maintain that. Also water wetter works great, definitly use it.

 

You might have a small air pocket in the cooling system when its cold jack the car up take off the radiator cap run it and look for air bubbles or drain it and vacuum fill the system that will cure any air problems you might have then go from there. I no what to do with the thermostat but nobody likes to here it...http://www.google.com/products/cata...T7lwe_uPjmBg&sa=X&oi=product_catalog_result&ct=result&resnum=4&ved=0CDMQ8wIwAw#...
First Law of Thermodynamics...
Q=mc(deltaT)

Q = heat removed
m = flow of coolant
c = specific heat capacity of coolant
deltaT = change in temperature of coolant in to coolant out .... Dah thats about the thermostat.

 

What gen BBC is it? Are you running aluminum heads? Single plane manifold? Some BBC's running steel heads and a single plane minfold without the water bypass hoses (running from front to rear on intake on both right and left sides) dont like it very much, expecially if there is any air in the system, this encompassed with what may be an early 454 (perhaps high nickel block) with .060 shaved outta it may be the root of you overheating...just some thoughts

 

180 degree thermostat opens at 180 degrees. so once the engine hits 180 the thermostat opens cool antifreeze from the rotator enters the engine and cools the thermostat down and it closes. engine heats it up and here we go again. Now the purpose for the thermostat is to allow time for the antifreeze to cool down in the rotator. if you put a 160 degree thermostat in the engine will run hotter because you have shortened the time the rotator has had to cool the antifreeze. once the antifreeze hits 160 it opens then closes but with a shorter cool time it opens sooner and sooner till it stays open and shortly after that your on the side of the road. I sagest you put in a 190 or 195. I have been in nock down arguments over this and won many a beer when I prove I'm right.:beerglass::beer::anim_32:

 

I agree with old willie .water is passing through the radiator to quickly to cool down. I also like to drill a .063 (1/16) hole in the thermostat body. this allows a very tiny amount of coolant to always flow and makes the thermostat more consistent so temp doesn't swing up and down as much also makes initial warm up a little smoother and a bit quicker . as much as I hate to admit it it is a ford factory idea that actually works. I do it on all my rods and it always seems to help.